Cross-site scripting in Python lxml module

1) Cross-site scripting

EUVDB-ID: #VU48793

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-27783

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data within lxml Python clean module. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

lxml: 1.2 - 4.6.1

CPE2.3

• cpe:2.3:a:freddix:lxml:1.2:*:*:*:*:python:*:*
• cpe:2.3:a:freddix:lxml:1.2.1:*:*:*:*:python:*:*
• cpe:2.3:a:freddix:lxml:1.3:*:*:*:*:python:*:*

External links

https://bugzilla.redhat.com/show_bug.cgi?id=1901633
https://github.com/lxml/lxml/commit/89e7aad6e7ff9ecd88678ff25f885988b184b26e
https://github.com/lxml/lxml/commit/a105ab8dc262ec6735977c25c13f0bdfcdec72a7

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.